Hitting Rewind

Fr. Thomas Berg

Some scientists are in hot pursuit of ethically acceptable alternatives that do not involve the destruction of embryos.

The South Korean cloning forgery last fall has given a new impetus to the pro-cloning movement in the United States. Scientists in the U.S. are seeking to be the first to produce stem cells from cloned human embryos. On April 13, word came that Harvard University had cleared stem-cell researcher Doug Melton to pursue human cloning. Melton is a Harvard researcher with his own 4,000 sq. ft. basement laboratory, the location of which is kept secret. It took a couple of years and lots of Harvard alumni dollars to audit Melton's funding to make sure that it was not coming from the federal government. His proposal to clone human beings was approved last month by three ethical review committees and two institutional review boards that oversee human research.

On May 6, the San Francisco Chronicle reported that scientists at the University of California, San Francisco, had recently received their requisite approvals from the university to begin a similar program. In addition to Harvard and UCSF, experts say that there are probably half a dozen other institutions across the country where cloning human embryos for stem cells is being attempted.

The goal is to accomplish what the disgraced Dr. Woo-Suk Hwang of Seoul National University failed to do: to create human embryos by cloning, then destroy the embryos in order to harvest stem cells from their remains. These stem cells--termed "pluripotent," which means they have the potential to become any cell in the body--would be genetically matched to the person who donated the cloned cells. They could then be used to grow tissues for future use in tissue replacement therapies (everything from regeneration of damaged heart tissue to Parkinson's to spinal chord injury). A perfect genetic match, these tissues would not be rejected by the donor's immune system.

Yet ardent advocates of cloning do not exhaust the field of embryonic stem cell researchers. After a recent meeting of the world's top stem-cell researchers sponsored by the Colorado-based Keystone Symposia last month, it became apparent that many advocates of such research do not share this newfound optimism for cloning as a source of patient-specific stem cells. According to one of the participants, Dr. Markus Grompe, who is a professor of molecular and medical genetics at Oregon Health & Science University in Portland, many researchers are now pouring their efforts into alternatives to cloning.

Grompe is a leading researcher in adult-stem-cell research and a board member of the International Society for Stem Cell Research, and he explained to me recently that many of the world's top names in embryonic-stem-cell research are now considering alternative approaches. He described how, in presentation after presentation at the exclusive meeting, researchers revealed that they are now investing their precious research dollars in ethically uncontroversial alternatives to cloning--uncontroversial because they would not involve the destruction of human embryos. "The intense interest in this area," he explained, "is driven by the realization that it will be technically extremely difficult and impractical to generate tissue-matched pluripotent stem cells by cloning." The meeting was animated by a real sense of imminent advances in these alternatives which the researchers believe will be just as useful to science and medicine as embryonic stem cells, and potentially more cost effective.

The alternatives under study share the common characteristic of seeking to produce human pluripotent stem cells without first creating and then damaging or destroying human embryos. One approach that is generating extraordinary interest is called cell reprogramming. In reprogramming, scientists would take any cell in the human body--a skin cell, for example--and "reprogram" that cell's nucleus such that the cell would take on all the characteristics of a pluripotent (embryonic) stem cell. The beauty of reprogramming is that it holds out the same promise as therapeutic cloning--tailor-made stem cells to match the patient--without killing embryos. In August of 2005, Dr. Kevin Eggan of Harvard University was able to show partial success in reprogramming using human cells, and Dr. Grompe assured me that a host of researchers are now in hot pursuit of making reprogramming work.

The hope of discovering ethically acceptable alternatives to embryo-destructive research and human cloning compelled Senators Arlen Specter and Rick Santorum--who normally conflict on the issue of embryonic-stem-cell research--to work together on a funding bill intended to intensify research into these alternatives. That bill, entitled the "Alternative Pluripotent Stem Cell Therapies Enhancement Act," was introduced by the two senators last Friday. It would promote research into methods of deriving pluripotent stem cells--such as reprogramming and "altered nuclear transfer"--which propose to do so without creating, harming, or destroying human embryos.

The field of regenerative medicine will continue to strive to unleash the power of stem cells to repair damaged tissue. Although the tally of advances in therapies derived from ethically uncontroversial adult stem cell research is on the rise daily, scientific interest in embryonic-stem-cell research is not going away any time soon. If it is true that embryonic stem cells hold the key to further advances, some innovative and free-thinking scientists may be forging the way to obtain the scientific equivalent of embryonic stem cells without creating or destroying embryos. It would be truly praiseworthy to see them achieve this without trampling on innocent human life.